Mark it out with the Rectangular Marquee Tool and make a copy of it: Edit ? Copy (ctrl+c). Get back to the previous window and insert it on a new layer: Edit ? Paste (ctrl+v). If that is necessary we may change the size, applying the next selection: Edit ? Free Transform (ctrl+t) (enlarging the picture preliminary with the Crop Tool).



Download now a set of ready to use brushes (downloaded here: http://www.deviantart.com/deviation/25147133/ ?qo=23&q=boost%3Apopular+in%3Aresources%2Fapplications%2Fpsbrushes+hair). Create a new layer: Layer ? New ? Layer and place it under the girl's layer. Now we have to copy the darkest colored zone on the girl's hair with the Eyedropper Tool and represent a coiffure out of her hair by applying the Brush Tool and the Free Transform option.



Merge down all these layers, but merging down the whole hair supposes using firstly the Clone Stamp Tool as a brush (1-3 px).



Then select the Brush Tool and several nuances to make the hair more voluminous:



Make the corrections on the layer's colors, applying Image ? Adjustments ? Color Balance (ctrl+b).



Process the same way the sky's layer (ctrl+b).